How lighting management in poultry production affects bird welfare through circadian biology and behavioral opportunities.
Lighting management is an often-overlooked welfare parameter in poultry production that affects bird biology at fundamental levels. Chickens are diurnal animals with complex visual systems adapted to full-spectrum natural light. Artificial lighting programs that optimize production through extended or continuous photoperiod disrupt circadian biology with welfare consequences across immune, reproductive, and behavioral systems. Providing minimum dark periods for sleep and rest, using full-spectrum lighting that includes UV-A wavelengths, and incorporating lighting programs that allow natural behavioral rhythms represent welfare improvements that many progressive producers have implemented. The regulatory floor of minimum dark periods represents a welfare floor rather than an optimal standard.